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Finding the Fourth Proportional to 855.28, 1,181.55 and 645.47

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Solution

The fourth proportional to 855.28, 1,181.55 and 645.47 is: 891.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.28 : 1,181.55 = 645.47 : x
  2. Step 2: Convert to fraction form
    855.28/1,181.55 = 645.47/x
  3. Step 3: Cross multiply
    855.28x = 1,181.55 × 645.47
  4. Step 4: Simplify right side
    855.28x = 762,653.30
  5. Step 5: Solve for x
    x = 762,653.30/855.28
  6. Step 6: Final answer
    x = 891.70

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.